Research And Simulated Analysis For Key Components Of Caragana Korshinskii Combine Harvester

Caragana korshinskii is one of the most significant ecological benefits wind prevention and sand fixation scrub plant, it is also an excellent available biomass resource. There is large area plantedof Caragana korshinskii in west China and north Shanxi loess plateau.Itsindustrial developmentandmechanized production has been widespread concerned in recent years. As the basic research such as itsmaterial propertiesaspectsis still lacking, we could onlyreference parameters of otherstalkplantsinstumping, conveyingtechnology and equipmentresearch and developmentdesign, which is inconsistent with the actual.In order to make full use of the Caragana korshinskii resources and guarantee the ecological benefits of the planting region, we designed the circular saw cutting component and the flexible hinge conveying mechanism based on Caragana stalk biomechanical property and its cutting, conveying mechanism. We conducted the dynamic analysis and field tests, and obtained the conclusions as follow:(1) We researched the physiology structure and biomechanical properties of Caragana korshinskii stalk. During the study, we established the hanging stick mechanical model of the Caragana stalk, and got the expression of density, moisture and friction coefficient et.al parameters by theoretical derivation. The tests determined the density of Caragana stalk was 0.48g/cm3, the moisture of Caragana stalk distributed between 30% and 60%, the friction coefficient between Caragana and metal was 0.353022. We obtained the tensile strength of Caragana stalk was 138N/mm2, and its share strength was 35N/mm2 by the tensile and share tests on the stalk. Orthogonal tests showed that the tensile breaking strength of Caragana stalk was related to its ages and cutting location, in which the ages influenced greater than cutting location, while its share breaking strength was only related to the ages, other than cutting location. Therefore we should consider the Caragana ages in the first place during the stumping operation, then take the cutting location into account.(2) Based on the biomechanical property and stumping mechanism of Caragana korshinskii, we studied the stumping situations and cutting methods under no support inertia cuttingcondition, and chose the circular saw as the cutting component of Caragana korshinskii harvester. We designed the circular saw cutting component by analyzing the parameters such as the saw body, sawtooth, and stability of circular saw. The analysis indicated that the lower of the stumping position, and the faster of cutting speed in safety, the inertia force and the reaction of Caragana stalk were bigger, it was more likely to reach the stumping target. The circular saw cutting component should avoid the critical speed of rotation when stumping.(3) Simulated analysis was conducted upon the circular saw cutting component of Caragana korshinskii harvester, and obtained main conclusions:① Kinematic analysis of the sawtooth and the next sawtooth in the circular saw was performed, we got the no-miss cutting condition of the circular saw, the biggest velocity ratio K was in direct proportion to the maximum forward velocity vm and sawtooth number. As the circular saw rotated in high speed during the practical stumping, there were multicut stumping and repeat stumping phenomenon.② Finite element modal analysis was performed upon the circular saw cutting component of high rotational speed. We obtained the former 6 stages vibration inherent frequency and the mode of vibration. The rotated velocity of circular saw was between 1500～1800 r/min during the practical stumping, the working frequency was 25～30 Hz, which avoid the first stage inherent frequency 0.015635 Hz and the second stage inherent frequency 371.85 Hz, therefore the modal construction of the cutting component was reasonable.③ Statics analysis was performed upon the circular saw cutting component, response surface design was adopted to analyze the strain and stress of the circular saw, we obtained the response surface matching expression of strain and stress. We got the conclusions by ridge analysis, when the thickness and the diameter of the circular saw were 6.5 mm and 450 mm respectively, the strain and stress in the circular saw were the minimum.④ Rigid-flexible coupling dynamic analysis was performed upon the circular saw cutting component and Caragana korshinskii. Simulated experiment was conducted at the 420 mm/s of circular saw forward speed, and obtained the force and torque curves of the contact point. Response surface design method was used to dynamic analysis of the rotate speed, thickness and diameter of the circular saw. The results indicated that the factors influenced on cutting force ranks rotate speed, thickness and diameter of the circular saw, the factors influenced upon cutting power ranks diameter, rotate speed and thickness of the circular saw, while each factor was significant. Ridge analysis showed that when the diameter, thickness and the rotate speed of the circular saw were 405.12 mm,5.15 mm and 1533.01 r/min, the stumping effect of the circular saw cutting component was best, and the stumping power of single component was expected between 10～13.3 kW.(4) We studied the operating principle of conveying mechanism in maize, sugarcane and cotton stalk harvester, and innovative designed the flexible hinge conveying mechanism to fit the transportation of Caragana korshinskii stalk, and built the solid model. The analysis between conveying speed in conveying mechanism and the forward speed of the Caragana combine harvester showed that when K between 2-3, which means the conveying speed of the conveyor mechanism was 2～3 times of the forward speed of the Caragana combine harvester, the conveying efficiency was best.(5) The field test of the circular saw cutting component for Caragana harvester indicated that the rotate speed, thickness and diameter of the circular saw influenced the stumping quality all, in which the rotate speed of the circular saw influenced the most, and the thickness of the circular saw took the second place. Therefore, the rotate speed and thickness of the circular saw should be considered firstly. The stumping efficiency of Caragana korshinskii was the most important indicator to value the Caragana harvester, the field test in this research showed that the harvester could achieve the stumping task, the stumping efficiency could reach at 88.7%, which was better than the former generations model machine.